A manhole cover launched 15 feet into the air in the middle of busy intersection near Union Square Monday morning, after a cable owned by Pacific Gas & Electric Co. apparently failed.
No cars were passing through the intersection of Grant and Post streets when the explosion occurred around 9:30 a.m.
“Luckily, nobody got hurt,” Officer Tom Cunnane said. “It could have been a Muni bus. It could have been anybody.”
Police closed passage to the intersection in all directions after the explosion.
Fire Department Battalion Chief Ed Gonzalez would not speculate as to what went wrong with the cable saying only that PG&E owns it and would investigate. “This is pretty bad ... [in an area] with this kind of traffic,” he said.
A witness walking to work was visibly shaken by the explosion, an officer said.
PG&E is investigating the incident.
PG&E spokesman Brian Swanson confirmed that the problem derived from a cable underground, not a transformer. There were no power outages, he said. “There’s redundancy built into the system,” Swanson said.
PG&E is currently replacing manhole covers in San Francisco with high-tech versions that stay in place when pressure builds up underground. In the event of a pressure build-up, the new manhole covers would essentially lift just enough to allow pressure underground to vent, Swanson said.
Just before 10:30 a.m., the manhole cover was put back in place and streets were beginning to be reopened.